A crew from Whittlesey was called to a bonfire in the garden of a home in Sycamore Road.
Firefighters used a hose reel to extinguish the fire and returned to their station by 9.47pm.
Cause of the fire was deliberate.
Anyone with information should contact police on 101 or call Crimestoppers anonymously on 0800 555 111.
For advice on bonfire safety, please click here.